src/common/sessiond-comm/sessiond-comm.c

   1 /*
   2  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
   3  *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License, version 2 only,
   7  * as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12  * more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include <assert.h>
  21 #include <limits.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <sys/stat.h>
  26 #include <sys/types.h>
  27 #include <unistd.h>
  28 #include <errno.h>
  29
  30 #include <common/defaults.h>
  31 #include <common/error.h>
  32
  33 #include "sessiond-comm.h"
  34
  35 /*
  36  * Human readable error message.
  37  */
  38 static const char *lttcomm_readable_code[] = {
  39         [ LTTCOMM_ERR_INDEX(LTTCOMM_OK) ] = "Success",
  40         [ LTTCOMM_ERR_INDEX(LTTCOMM_ERR) ] = "Unknown error",
  41         [ LTTCOMM_ERR_INDEX(LTTCOMM_UND) ] = "Undefined command",
  42         [ LTTCOMM_ERR_INDEX(LTTCOMM_NOT_IMPLEMENTED) ] = "Not implemented",
  43         [ LTTCOMM_ERR_INDEX(LTTCOMM_UNKNOWN_DOMAIN) ] = "Unknown tracing domain",
  44         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_SESSION) ] = "No session found",
  45         [ LTTCOMM_ERR_INDEX(LTTCOMM_LIST_FAIL) ] = "Unable to list traceable apps",
  46         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_APPS) ] = "No traceable apps found",
  47         [ LTTCOMM_ERR_INDEX(LTTCOMM_SESS_NOT_FOUND) ] = "Session name not found",
  48         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACE) ] = "No trace found",
  49         [ LTTCOMM_ERR_INDEX(LTTCOMM_FATAL) ] = "Fatal error of the session daemon",
  50         [ LTTCOMM_ERR_INDEX(LTTCOMM_CREATE_DIR_FAIL) ] = "Create directory failed",
  51         [ LTTCOMM_ERR_INDEX(LTTCOMM_START_FAIL) ] = "Start trace failed",
  52         [ LTTCOMM_ERR_INDEX(LTTCOMM_STOP_FAIL) ] = "Stop trace failed",
  53         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_TRACEABLE) ] = "App is not traceable",
  54         [ LTTCOMM_ERR_INDEX(LTTCOMM_SELECT_SESS) ] = "A session MUST be selected",
  55         [ LTTCOMM_ERR_INDEX(LTTCOMM_EXIST_SESS) ] = "Session name already exist",
  56         [ LTTCOMM_ERR_INDEX(LTTCOMM_CONNECT_FAIL) ] = "Unable to connect to Unix socket",
  57         [ LTTCOMM_ERR_INDEX(LTTCOMM_APP_NOT_FOUND) ] = "Application not found",
  58         [ LTTCOMM_ERR_INDEX(LTTCOMM_EPERM) ] = "Permission denied",
  59         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NA) ] = "Kernel tracer not available",
  60         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_VERSION) ] = "Kernel tracer version is not compatible",
  61         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_EVENT_EXIST) ] = "Kernel event already exists",
  62         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_SESS_FAIL) ] = "Kernel create session failed",
  63         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_FAIL) ] = "Kernel create channel failed",
  64         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_NOT_FOUND) ] = "Kernel channel not found",
  65         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_DISABLE_FAIL) ] = "Disable kernel channel failed",
  66         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CHAN_ENABLE_FAIL) ] = "Enable kernel channel failed",
  67         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONTEXT_FAIL) ] = "Add kernel context failed",
  68         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_ENABLE_FAIL) ] = "Enable kernel event failed",
  69         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DISABLE_FAIL) ] = "Disable kernel event failed",
  70         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_META_FAIL) ] = "Opening metadata failed",
  71         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_START_FAIL) ] = "Starting kernel trace failed",
  72         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STOP_FAIL) ] = "Stoping kernel trace failed",
  73         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_CONSUMER_FAIL) ] = "Kernel consumer start failed",
  74         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_STREAM_FAIL) ] = "Kernel create stream failed",
  75         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_FAIL) ] = "Kernel trace directory creation failed",
  76         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_DIR_EXIST) ] = "Kernel trace directory already exist",
  77         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_NO_SESSION) ] = "No kernel session found",
  78         [ LTTCOMM_ERR_INDEX(LTTCOMM_KERN_LIST_FAIL) ] = "Listing kernel events failed",
  79         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CALIBRATE_FAIL) ] = "UST calibration failed",
  80         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_VERSION) ] = "UST tracer version is not compatible",
  81         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_SESS_FAIL) ] = "UST create session failed",
  82         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_FAIL) ] = "UST create channel failed",
  83         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_EXIST) ] = "UST channel already exist",
  84         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_NOT_FOUND) ] = "UST channel not found",
  85         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_DISABLE_FAIL) ] = "Disable UST channel failed",
  86         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CHAN_ENABLE_FAIL) ] = "Enable UST channel failed",
  87         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_FAIL) ] = "Add UST context failed",
  88         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_ENABLE_FAIL) ] = "Enable UST event failed",
  89         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DISABLE_FAIL) ] = "Disable UST event failed",
  90         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_META_FAIL) ] = "Opening metadata failed",
  91         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_START_FAIL) ] = "Starting UST trace failed",
  92         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_STOP_FAIL) ] = "Stoping UST trace failed",
  93         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONSUMER64_FAIL) ] = "64-bit UST consumer start failed",
  94         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONSUMER32_FAIL) ] = "32-bit UST consumer start failed",
  95         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_STREAM_FAIL) ] = "UST create stream failed",
  96         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DIR_FAIL) ] = "UST trace directory creation failed",
  97         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_DIR_EXIST) ] = "UST trace directory already exist",
  98         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_NO_SESSION) ] = "No UST session found",
  99         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_LIST_FAIL) ] = "Listing UST events failed",
 100         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_EVENT_EXIST) ] = "UST event already exist",
 101         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_EVENT_NOT_FOUND)] = "UST event not found",
 102         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_EXIST)] = "UST context already exist",
 103         [ LTTCOMM_ERR_INDEX(LTTCOMM_UST_CONTEXT_INVAL)] = "UST invalid context",
 104         [ LTTCOMM_ERR_INDEX(LTTCOMM_NEED_ROOT_SESSIOND) ] = "Tracing the kernel requires a root lttng-sessiond daemon and \"tracing\" group user membership",
 105         [ LTTCOMM_ERR_INDEX(LTTCOMM_TRACE_ALREADY_STARTED) ] = "Tracing already started",
 106         [ LTTCOMM_ERR_INDEX(LTTCOMM_TRACE_ALREADY_STOPPED) ] = "Tracing already stopped",
 107
 108         [ LTTCOMM_ERR_INDEX(CONSUMERD_COMMAND_SOCK_READY) ] = "consumerd command socket ready",
 109         [ LTTCOMM_ERR_INDEX(CONSUMERD_SUCCESS_RECV_FD) ] = "consumerd success on receiving fds",
 110         [ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_FD) ] = "consumerd error on receiving fds",
 111         [ LTTCOMM_ERR_INDEX(CONSUMERD_ERROR_RECV_CMD) ] = "consumerd error on receiving command",
 112         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_ERROR) ] = "consumerd error in polling thread",
 113         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_NVAL) ] = "consumerd polling on closed fd",
 114         [ LTTCOMM_ERR_INDEX(CONSUMERD_POLL_HUP) ] = "consumerd all fd hung up",
 115         [ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_SUCCESS) ] = "consumerd exiting normally",
 116         [ LTTCOMM_ERR_INDEX(CONSUMERD_EXIT_FAILURE) ] = "consumerd exiting on error",
 117         [ LTTCOMM_ERR_INDEX(CONSUMERD_OUTFD_ERROR) ] = "consumerd error opening the tracefile",
 118         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EBADF) ] = "consumerd splice EBADF",
 119         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_EINVAL) ] = "consumerd splice EINVAL",
 120         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ENOMEM) ] = "consumerd splice ENOMEM",
 121         [ LTTCOMM_ERR_INDEX(CONSUMERD_SPLICE_ESPIPE) ] = "consumerd splice ESPIPE",
 122         [ LTTCOMM_ERR_INDEX(LTTCOMM_NO_EVENT) ] = "Event not found",
 123         [ LTTCOMM_ERR_INDEX(LTTCOMM_INVALID) ] = "Invalid parameter",
 124 };
 125
 126 /*
 127  * Return ptr to string representing a human readable error code from the
 128  * lttcomm_return_code enum.
 129  *
 130  * These code MUST be negative in other to treat that as an error value.
 131  */
 132 const char *lttcomm_get_readable_code(enum lttcomm_return_code code)
 133 {
 134         int tmp_code = -code;
 135
 136         if (tmp_code >= LTTCOMM_OK && tmp_code < LTTCOMM_NR) {
 137                 return lttcomm_readable_code[LTTCOMM_ERR_INDEX(tmp_code)];
 138         }
 139
 140         return "Unknown error code";
 141 }
 142
 143 /*
 144  * Connect to unix socket using the path name.
 145  */
 146 int lttcomm_connect_unix_sock(const char *pathname)
 147 {
 148         struct sockaddr_un sun;
 149         int fd, ret, closeret;
 150
 151         fd = socket(PF_UNIX, SOCK_STREAM, 0);
 152         if (fd < 0) {
 153                 PERROR("socket");
 154                 ret = fd;
 155                 goto error;
 156         }
 157
 158         memset(&sun, 0, sizeof(sun));
 159         sun.sun_family = AF_UNIX;
 160         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 161         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 162
 163         ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
 164         if (ret < 0) {
 165                 /*
 166                  * Don't print message on connect error, because connect is used in
 167                  * normal execution to detect if sessiond is alive.
 168                  */
 169                 goto error_connect;
 170         }
 171
 172         return fd;
 173
 174 error_connect:
 175         closeret = close(fd);
 176         if (closeret) {
 177                 PERROR("close");
 178         }
 179 error:
 180         return ret;
 181 }
 182
 183 /*
 184  * Do an accept(2) on the sock and return the new file descriptor. The socket
 185  * MUST be bind(2) before.
 186  */
 187 int lttcomm_accept_unix_sock(int sock)
 188 {
 189         int new_fd;
 190         struct sockaddr_un sun;
 191         socklen_t len = 0;
 192
 193         /* Blocking call */
 194         new_fd = accept(sock, (struct sockaddr *) &sun, &len);
 195         if (new_fd < 0) {
 196                 PERROR("accept");
 197         }
 198
 199         return new_fd;
 200 }
 201
 202 /*
 203  * Creates a AF_UNIX local socket using pathname bind the socket upon creation
 204  * and return the fd.
 205  */
 206 int lttcomm_create_unix_sock(const char *pathname)
 207 {
 208         struct sockaddr_un sun;
 209         int fd;
 210         int ret = -1;
 211
 212         /* Create server socket */
 213         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 214                 PERROR("socket");
 215                 goto error;
 216         }
 217
 218         memset(&sun, 0, sizeof(sun));
 219         sun.sun_family = AF_UNIX;
 220         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 221         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 222
 223         /* Unlink the old file if present */
 224         (void) unlink(pathname);
 225         ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
 226         if (ret < 0) {
 227                 PERROR("bind");
 228                 goto error;
 229         }
 230
 231         return fd;
 232
 233 error:
 234         return ret;
 235 }
 236
 237 /*
 238  * Make the socket listen using LTTNG_SESSIOND_COMM_MAX_LISTEN.
 239  */
 240 int lttcomm_listen_unix_sock(int sock)
 241 {
 242         int ret;
 243
 244         ret = listen(sock, LTTNG_SESSIOND_COMM_MAX_LISTEN);
 245         if (ret < 0) {
 246                 PERROR("listen");
 247         }
 248
 249         return ret;
 250 }
 251
 252 /*
 253  * Receive data of size len in put that data into the buf param. Using recvmsg
 254  * API.
 255  *
 256  * Return the size of received data.
 257  */
 258 ssize_t lttcomm_recv_unix_sock(int sock, void *buf, size_t len)
 259 {
 260         struct msghdr msg;
 261         struct iovec iov[1];
 262         ssize_t ret = -1;
 263
 264         memset(&msg, 0, sizeof(msg));
 265
 266         iov[0].iov_base = buf;
 267         iov[0].iov_len = len;
 268         msg.msg_iov = iov;
 269         msg.msg_iovlen = 1;
 270
 271         do {
 272                 ret = recvmsg(sock, &msg, MSG_WAITALL);
 273         } while (ret < 0 && errno == EINTR);
 274         if (ret < 0) {
 275                 PERROR("recvmsg");
 276         }
 277
 278         return ret;
 279 }
 280
 281 /*
 282  * Send buf data of size len. Using sendmsg API.
 283  *
 284  * Return the size of sent data.
 285  */
 286 ssize_t lttcomm_send_unix_sock(int sock, void *buf, size_t len)
 287 {
 288         struct msghdr msg;
 289         struct iovec iov[1];
 290         ssize_t ret = -1;
 291
 292         memset(&msg, 0, sizeof(msg));
 293
 294         iov[0].iov_base = buf;
 295         iov[0].iov_len = len;
 296         msg.msg_iov = iov;
 297         msg.msg_iovlen = 1;
 298
 299         ret = sendmsg(sock, &msg, 0);
 300         if (ret < 0) {
 301                 /*
 302                  * Only warn about EPIPE when quiet mode is deactivated.
 303                  * We consider EPIPE as expected.
 304                  */
 305                 if (errno != EPIPE || !lttng_opt_quiet) {
 306                         PERROR("sendmsg");
 307                 }
 308         }
 309
 310         return ret;
 311 }
 312
 313 /*
 314  * Shutdown cleanly a unix socket.
 315  */
 316 int lttcomm_close_unix_sock(int sock)
 317 {
 318         int ret, closeret;
 319
 320         /* Shutdown receptions and transmissions */
 321         ret = shutdown(sock, SHUT_RDWR);
 322         if (ret < 0) {
 323                 PERROR("shutdown");
 324         }
 325
 326         closeret = close(sock);
 327         if (closeret) {
 328                 PERROR("close");
 329         }
 330
 331         return ret;
 332 }
 333
 334 /*
 335  * Send a message accompanied by fd(s) over a unix socket.
 336  *
 337  * Returns the size of data sent, or negative error value.
 338  */
 339 ssize_t lttcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 340 {
 341         struct msghdr msg;
 342         struct cmsghdr *cmptr;
 343         struct iovec iov[1];
 344         ssize_t ret = -1;
 345         unsigned int sizeof_fds = nb_fd * sizeof(int);
 346         char tmp[CMSG_SPACE(sizeof_fds)];
 347         char dummy = 0;
 348
 349         memset(&msg, 0, sizeof(msg));
 350
 351         if (nb_fd > LTTCOMM_MAX_SEND_FDS)
 352                 return -EINVAL;
 353
 354         msg.msg_control = (caddr_t)tmp;
 355         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 356
 357         cmptr = CMSG_FIRSTHDR(&msg);
 358         cmptr->cmsg_level = SOL_SOCKET;
 359         cmptr->cmsg_type = SCM_RIGHTS;
 360         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 361         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 362         /* Sum of the length of all control messages in the buffer: */
 363         msg.msg_controllen = cmptr->cmsg_len;
 364
 365         iov[0].iov_base = &dummy;
 366         iov[0].iov_len = 1;
 367         msg.msg_iov = iov;
 368         msg.msg_iovlen = 1;
 369
 370         ret = sendmsg(sock, &msg, 0);
 371         if (ret < 0) {
 372                 /*
 373                  * Only warn about EPIPE when quiet mode is deactivated.
 374                  * We consider EPIPE as expected.
 375                  */
 376                 if (errno != EPIPE || !lttng_opt_quiet) {
 377                         PERROR("sendmsg");
 378                 }
 379         }
 380         return ret;
 381 }
 382
 383 /*
 384  * Recv a message accompanied by fd(s) from a unix socket.
 385  *
 386  * Returns the size of received data, or negative error value.
 387  *
 388  * Expect at most "nb_fd" file descriptors. Returns the number of fd
 389  * actually received in nb_fd.
 390  */
 391 ssize_t lttcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd)
 392 {
 393         struct iovec iov[1];
 394         ssize_t ret = 0;
 395         struct cmsghdr *cmsg;
 396         size_t sizeof_fds = nb_fd * sizeof(int);
 397         char recv_fd[CMSG_SPACE(sizeof_fds)];
 398         struct msghdr msg;
 399         char dummy;
 400
 401         memset(&msg, 0, sizeof(msg));
 402
 403         /* Prepare to receive the structures */
 404         iov[0].iov_base = &dummy;
 405         iov[0].iov_len = 1;
 406         msg.msg_iov = iov;
 407         msg.msg_iovlen = 1;
 408         msg.msg_control = recv_fd;
 409         msg.msg_controllen = sizeof(recv_fd);
 410
 411         do {
 412                 ret = recvmsg(sock, &msg, 0);
 413         } while (ret < 0 && errno == EINTR);
 414         if (ret < 0) {
 415                 PERROR("recvmsg fds");
 416                 goto end;
 417         }
 418         if (ret != 1) {
 419                 fprintf(stderr, "Error: Received %zd bytes, expected %d\n",
 420                                 ret, 1);
 421                 goto end;
 422         }
 423         if (msg.msg_flags & MSG_CTRUNC) {
 424                 fprintf(stderr, "Error: Control message truncated.\n");
 425                 ret = -1;
 426                 goto end;
 427         }
 428         cmsg = CMSG_FIRSTHDR(&msg);
 429         if (!cmsg) {
 430                 fprintf(stderr, "Error: Invalid control message header\n");
 431                 ret = -1;
 432                 goto end;
 433         }
 434         if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
 435                 fprintf(stderr, "Didn't received any fd\n");
 436                 ret = -1;
 437                 goto end;
 438         }
 439         if (cmsg->cmsg_len != CMSG_LEN(sizeof_fds)) {
 440                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 441                                 (size_t) cmsg->cmsg_len, (size_t) CMSG_LEN(sizeof_fds));
 442                 ret = -1;
 443                 goto end;
 444         }
 445         memcpy(fds, CMSG_DATA(cmsg), sizeof_fds);
 446         ret = sizeof_fds;
 447 end:
 448         return ret;
 449 }
 450
 451 /*
 452  * Send a message with credentials over a unix socket.
 453  *
 454  * Returns the size of data sent, or negative error value.
 455  */
 456 ssize_t lttcomm_send_creds_unix_sock(int sock, void *buf, size_t len)
 457 {
 458         struct msghdr msg;
 459         struct iovec iov[1];
 460         ssize_t ret = -1;
 461 #ifdef __linux__
 462         struct cmsghdr *cmptr;
 463         size_t sizeof_cred = sizeof(lttng_sock_cred);
 464         char anc_buf[CMSG_SPACE(sizeof_cred)];
 465         lttng_sock_cred *creds;
 466 #endif /* __linux__ */
 467
 468         memset(&msg, 0, sizeof(msg));
 469
 470         iov[0].iov_base = buf;
 471         iov[0].iov_len = len;
 472         msg.msg_iov = iov;
 473         msg.msg_iovlen = 1;
 474
 475 #ifdef __linux__
 476         msg.msg_control = (caddr_t) anc_buf;
 477         msg.msg_controllen = CMSG_LEN(sizeof_cred);
 478
 479         cmptr = CMSG_FIRSTHDR(&msg);
 480         cmptr->cmsg_level = SOL_SOCKET;
 481         cmptr->cmsg_type = LTTNG_SOCK_CREDS;
 482         cmptr->cmsg_len = CMSG_LEN(sizeof_cred);
 483
 484         creds = (lttng_sock_cred*) CMSG_DATA(cmptr);
 485
 486         LTTNG_SOCK_SET_UID_CRED(creds, geteuid());
 487         LTTNG_SOCK_SET_GID_CRED(creds, getegid());
 488         LTTNG_SOCK_SET_PID_CRED(creds, getpid());
 489 #endif /* __linux__ */
 490
 491         ret = sendmsg(sock, &msg, 0);
 492         if (ret < 0) {
 493                 /*
 494                  * Only warn about EPIPE when quiet mode is deactivated.
 495                  * We consider EPIPE as expected.
 496                  */
 497                 if (errno != EPIPE || !lttng_opt_quiet) {
 498                         PERROR("sendmsg");
 499                 }
 500         }
 501         return ret;
 502 }
 503
 504 /*
 505  * Recv a message accompanied with credentials from a unix socket.
 506  *
 507  * Returns the size of received data, or negative error value.
 508  */
 509 ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len,
 510                 lttng_sock_cred *creds)
 511 {
 512         struct msghdr msg;
 513         struct iovec iov[1];
 514         ssize_t ret;
 515 #ifdef __linux__
 516         struct cmsghdr *cmptr;
 517         size_t sizeof_cred = sizeof(lttng_sock_cred);
 518         char anc_buf[CMSG_SPACE(sizeof_cred)];
 519 #endif  /* __linux__ */
 520
 521         memset(&msg, 0, sizeof(msg));
 522
 523         /* Not allowed */
 524         if (creds == NULL) {
 525                 ret = -1;
 526                 goto end;
 527         }
 528
 529         /* Prepare to receive the structures */
 530         iov[0].iov_base = buf;
 531         iov[0].iov_len = len;
 532         msg.msg_iov = iov;
 533         msg.msg_iovlen = 1;
 534
 535 #ifdef __linux__
 536         msg.msg_control = anc_buf;
 537         msg.msg_controllen = sizeof(anc_buf);
 538 #endif /* __linux__ */
 539
 540         do {
 541                 ret = recvmsg(sock, &msg, 0);
 542         } while (ret < 0 && errno == EINTR);
 543         if (ret < 0) {
 544                 PERROR("recvmsg fds");
 545                 goto end;
 546         }
 547
 548 #ifdef __linux__
 549         if (msg.msg_flags & MSG_CTRUNC) {
 550                 fprintf(stderr, "Error: Control message truncated.\n");
 551                 ret = -1;
 552                 goto end;
 553         }
 554
 555         cmptr = CMSG_FIRSTHDR(&msg);
 556         if (cmptr == NULL) {
 557                 fprintf(stderr, "Error: Invalid control message header\n");
 558                 ret = -1;
 559                 goto end;
 560         }
 561
 562         if (cmptr->cmsg_level != SOL_SOCKET ||
 563                         cmptr->cmsg_type != LTTNG_SOCK_CREDS) {
 564                 fprintf(stderr, "Didn't received any credentials\n");
 565                 ret = -1;
 566                 goto end;
 567         }
 568
 569         if (cmptr->cmsg_len != CMSG_LEN(sizeof_cred)) {
 570                 fprintf(stderr, "Error: Received %zu bytes of ancillary data, expected %zu\n",
 571                                 (size_t) cmptr->cmsg_len, (size_t) CMSG_LEN(sizeof_cred));
 572                 ret = -1;
 573                 goto end;
 574         }
 575
 576         memcpy(creds, CMSG_DATA(cmptr), sizeof_cred);
 577 #elif defined(__FreeBSD__)
 578         {
 579                 int peer_ret;
 580
 581                 peer_ret = getpeereid(sock, &creds->uid, &creds->gid);
 582                 if (peer_ret != 0) {
 583                         return peer_ret;
 584                 }
 585         }
 586 #else
 587 #error "Please implement credential support for your OS."
 588 #endif  /* __linux__ */
 589
 590 end:
 591         return ret;
 592 }
 593
 594 /*
 595  * Set socket option to use credentials passing.
 596  */
 597 #ifdef __linux__
 598 int lttcomm_setsockopt_creds_unix_sock(int sock)
 599 {
 600         int ret, on = 1;
 601
 602         /* Set socket for credentials retrieval */
 603         ret = setsockopt(sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 604         if (ret < 0) {
 605                 PERROR("setsockopt creds unix sock");
 606         }
 607         return ret;
 608 }
 609 #elif defined(__FreeBSD__)
 610 int lttcomm_setsockopt_creds_unix_sock(int sock)
 611 {
 612         return 0;
 613 }
 614 #else
 615 #error "Please implement credential support for your OS."
 616 #endif /* __linux__ */